The disclosed technology relates to compounds that are useful as seal swell agents in lubricant compositions. Also disclosed are lubricating compositions and concentrates comprising said seal swell agents and to the use of such lubricating compositions and concentrates.
Rubber seals are critically important to the proper operation of many engines, power transmission devices, pumps, gears and bearings. Seal performance tends to deteriorate with use and age; seals tend to degrade, harden, shrink and then leak. Preserving the integrity of seals in such devices is desirable, in order to lower maintenance costs of the operation and to prevent unexpected loss or leakage of lubricant that could result in catastrophic mechanical failure.
It is known to introduce seal swelling additives into functional fluids used in machinery in order to alleviate the problems of seal shrinkage and subsequent leakage of the functional fluid. The enhancement of swelling or apparent regeneration of elastomeric seals in machinery and equipment aids the prevention of leakage due to shrinkage of seals over time.
US 2007/0087947 A1 (Michael Glasgow et al., published on 19 Apr. 2007) discloses an additive composition which comprises at least one dispersant viscosity index improver and at least two seal swell additives. The two seal swell additives can be selected from oil-soluble esters and oil soluble sulfones such as the sulfolane seal well agents disclosed in U.S. Pat. Nos. 4,029,587 and 4,029,588.
U.S. Pat. No. 7,727,944 B2 (Edward J. Konzman et al., published on 1 Jun. 2010) discloses an additive composition which comprises a combination of conditioning agents for preserving the integrity of elastomeric materials. The composition can comprise as component (B), a second seal-conditioning agent which is a seal swell agent selected from the group consisting of sulfolanes, benzyl esters, lactones, nitriles and hindered phenolic materials.
There is a need for new lubricating compositions (lubricants) that have excellent seal swelling properties. There is a need for new compounds that can act as seal swell agents in lubricants and that impart excellent seal compatibility and, in particular, seal swelling properties to said lubricants.